A current to pulse-sequence transducer for transforming a current to be measured into a sequence of pulses, including means for transforming the current to be measured into a measurement magnetic field having a strength substantially linearly proportional to the current to be measured, means for generating a reference magnetic field, and magnetic field comparison means has already been proposed in Swiss patent application No. 7235/80-1 since published as DE-OS No. 30 39 715; an alternate circuit using magnetoresistive thin films has become known from the publication "IEEE Transactions on Magnetics" Vol. MAG-12, No. 6, November 1976, entitled "A Permalloy Current Sensor", pages 813-815.
Current to pulse-sequence transducers of the aforedescribed kind may, for example, be used as components of a mark-to-space modulator, employed, for example in electricity consumption meters, such as disclosed, for example, in Schneider et al., U.S. Pat. No. 4,291,377, assigned to the assignee of the present invention. In a mark-to-space modulator of this kind, as is known, there is generated a rapid sequence of pulses having a mark-to-space ratio proportional to an input value, for example the value of a current to be measured.
The accuracy of current to pulse-sequence transducers of the aforedescribed kind is, however, influenced by any imbalance, or D.C. offset from a normally zero output when the magnetic fields applied to magnetic field comparison means in the current to pulse-sequence transducer are equal, and is also subject to external electromagnetic disturbances picked up by the transducer.